I would highly recommend Hcube BKK to any travellers looking for a place close to BKK airport and the ARL, it's also not so far from the centre of Bangkok if you want to take the train in.
The two bedroom apartment we stayed in was clean, comfortable and stylish. The bed was one of the most comfortable I've slept in with very high quality bed sheets.
The host & staff were quick to respond, very friendly and helpful and provided lots of info for directions and nearby food & stores.